The Government lost the vote on an opposition bill to abolish upward-only rent reviews by 27 votes to 23 due to the absence of the Senators Jimmy Harte, John Kelly, Denis Landy and John Whelan.

There is no blame being attached within Labour to Mr Harte, who was attending a business meeting in Liverpool at the time of the vote.

But there are strong feelings within the party about the absence of Mr Kelly, Mr Landy and Mr Whelan who are regarded as hostile to the leadership of Tanaiste Eamon Gilmore and have all gone canvassing against the abolition of the Seanad.

But the four missing Labour senators were expected to be let off by Labour chief whip Emmet Stagg due to the fact that they did not actually vote against the Government position.

A Labour source said that while voting against a Budget measure would be an "11 out of 10" offence, missing a vote on an opposition bill was at the lowest end of the scale.

There was no chance of the ultimate sanction – losing the party whip – being applied.

Mr Gilmore has been trying to steady nerves in the party after a dismal 6pc opinion poll rating.

One Labour source said that the opposition appeared to be very well prepared to take advantage of the missing Labour senators, with far more opposition senators in the chamber than was normal.

And they got the support of rebel Fine Gael senators Paul Bradford and Fidelma Healy-Eames, rebel Labour senator James Heffernan, and six of Taoiseach Enda Kenny's nominated senators.

But Mr Whelan said nothing had been orchestrated between the senators "even though it could appear that way".

"The vote was called and we had already gone home," he said.

Mr Landy said he was attending another event and had arranged to have a "pair" with Fianna Fail's Jim Walsh – an arrangement which meant that both of them did not take part in the vote.

"He wasn't in the chamber and I wasn't in the chamber. There's nothing sinister about this whatsoever. I acted in good faith," he said. Mr Kelly could not be contacted for comment

Labour Seanad chief whip Aideen Hayden said she would be sending a report to party chief whip Emmet Stagg.

Labour sources admit there was "genuine confusion" over whether there would actually be a vote on the bill.